High Voltage Mg-Ion Battery Cathode via a Solid Solution Cr-Mn Spinel Oxide
High Voltage Mg-Ion Battery Cathode via a Solid Solution Cr-Mn Spinel Oxide
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DOI：
10.1021/acs.chemmater.0c01988
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发表时间：
2020-08-11
影响因子：
8.6
通讯作者：
Key, Baris
中科院分区：
文献类型：
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作者：
Kwon, Bob Jin;Yin, Liang;Key, Baris
晶格Mg2+在定制固溶型尖晶石MgCrMnO4中，在非水电解质中以高锰氧化还原电位电化学利用。来自实验和理论分析的补充证据支持在设计的氧化框架中存在大量Mg2+ (de)插入，其中Mg2+和O2-之间存在强静电相互作用。在350℃退火后，将尖晶石中的Mg/Mn反位相降低到10%左右，进一步提高了Mg2+的迁移率。去除Mg2+后，尖晶石晶格未发生任何相变，表明该材料在带电状态下具有类似于3.0 V （vs Mg/Mel）的高电位稳定性。第一次放电时明显的再镁化，在60℃下收获高达180 Wh/kg。在重镁状态下，检测到Mg2+插入尖晶石的间隙位置，可能导致部分可逆性，需要解决结构稳定性问题。这些观察结果为使用尖晶石氧化物开发实用的高压镁离子阴极提供了第一个明确的途径。
Lattice Mg2+ in a tailored solid solution spinel, MgCrMnO4, is electrochemically utilized at high Mn-redox potentials in a nonaqueous electrolyte. Complementary evidence from experimental and theoretical analyses supports bulk Mg2+ (de)intercalation throughout the designed oxide frame where strong electrostatic interaction between Mg2+ and O2- exists. Mg/Mn antisite inversion in the spinel is lowered to similar to 10% via postannealing at 350 degrees C to further improve Mg2+ mobility. Spinel lattice is preserved upon removal of Mg2+ without any phase transformations, denoting structural stability at the charged state at a high potential similar to 3.0 V (vs Mg/Mel. Clear remagnesiation upon first discharge, harvesting up to similar to 180 Wh/kg at 60 degrees C is shown. In the remagnesiated state, insertion of Mg2+ into interstitial sites in the spinel is detected, possibly resulting in partial reversibility which needs to be addressed for structural stability. The observations constitute a first clear path to the development of a practical high voltage Mg-ion cathode using a spinel oxide.